LONDON - Brief rests, alternating with bouts of exercise, are crucial in maintaining fitness, allowing muscles to recover and help shape up the body faster, says a new study.

The research by University of Stirling, Scotland, split cyclists into two groups. One did bursts of high intensity exercise interspersed with short rest periods three times each week.

In each session, they pedalled hard but below sprint pace for four minutes and then stopped for two minutes before repeating the pattern five times.

The second group rode continuously for an hour at a slightly easier pace, three times a week. After four weeks, the two groups swapped programmes, the Daily Mail reports.

Tests showed the first programme, which involved a mixture of tough training and taking it easy, to be the most beneficial, leading to twice as big an improvement in power and performance.

Exercise physiologist Stuart Galloway from the university, said: “It is a case of training smarter. We found in these cyclists that if you can make the hard sessions harder and the easy sessions easier, you are likely to see better progress.”

”Amateur athletes tend to spend a lot of their training in the moderate intensity bracket, which showed smaller improvements in our study. For the wider public, most people were advised to do moderate intensity exercise for around three hours a week.”